The Animal Kingdom's Top Marathoners

Compared to other land mammals, humans are remarkably good at running long distances. Our upright posture and ability to shed heat—through sweating—are what allow people to run more than 20 miles during a race. Very few other animals can sustain such distances, especially at the speeds that top human athletes perform. But there is plenty of competition out there—nature is full of species adapted for running distance. Here's a look at six of the best marathoners in the animal kingdom, from slowest to fastest.

Horses

Horses

Max Speed:

54 mph

Average Speed for 20+ miles:

10.5 mph

Estimated Marathon Time:

2.5 Hours

Through years of selective breeding, racehorses have gained a built-in biological mechanism for efficient blood—the kind that certain human athletes can only achieve by doping. "When they start to exercise, their spleen will kick out a whole bunch of red bloods cells into their system, into their cardiovascular system to make the oxygen carrying capacity of their blood go up," says Peter Weyand, professor of physiology and biomechanics at Southern Methodist University. Human blood dopers transfuse blood before a race to achieve an increased aerobic capacity. However, the horse naturally release blood cells moments after starting to a gallop.

For the last 30 years, the Welsh town of Llanwrtyd Wells has hoted a 22-mile, man-versus-horse race. Humans have only won the race twice, but top runners usually only finish 10 minutes after the animals. Where horses exceed in oxygen efficiency, humans make up for in temperature regulation. In the beginning of the race the horses tend to have a 30 minute lead, but toward the end, that advantaged is cut to a couple of minutes. Over the course of the race, humans are more efficient at expelling heat—not to mention they aren't running with a rider on their back. On a hot day, humans can win much more easily.

Humans

Humans

Max Speed:

27.45 mph (Usain Bolt, 100 meters)

Average Speed for 20+ Miles:

12.7 mph (Haile Gebrselassie)

Best Marathon Time:

2:03:59 (Haile Gebrselassie, Berlin)

Are humans born to run? Some experts think that humans have, indeed, evolved to be distance runners—the better to track prey, evade predators and migrate. While there is some debate on running and human evolution, there is no question that we are up there in the animal kingdom for speeds at marathon distances. There is no one reason, but the efficiency of our cooling systems—our ability to sweat—and having an upright posture, to minimize our sun exposure and maximize our lung capacity, are some of the primary reasons we are skilled distance runners.

One major difference between humans and animals is that we don't have in-born endurance; we have to train. Peter Weyand says that compared to other animals, humans have a high energy cost of running—we spend more energy in each stride relative to our size. But unlike wild animals, we can motivate ourselves to run, and through training we can increase our aerobic scope—the amount of aerobic activity one can achieve. "Even though [humans] are good at regulating heat, they have more heat to dump because their economy is poor," he says. Strict training regimens and the ability to sweat can make up for that lack.